JPS60135573A - Method and device for sputtering - Google Patents

Abstract

PURPOSE:To increase the sticking and deposition rate of target atoms or particles to a substrate by accelerating the ions in the high density plasma covering the surface of a target by an electric field so as to collide against the surface of the target. CONSTITUTION:The plasma of high density from a microwave power source 35 is transferred to the surface of a target 21 and the surface of the target 21 is covered with plasma 43 of high density. The ions in the plasma 43 are then accelerated by the electric field impressed from a power source 30 so as to collide against the surface of the target 21. The atoms or particles driven off from the target 21 are stuck onto a substrate 31.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sputtering method and apparatus used in a thin film manufacturing process for semiconductor devices and the like.

[Background of the invention]

In sputtering film formation, a low-pressure atmospheric gas (for example, Ar) causes total glow emission and ionization, and plasma-like atmospheric gas ions are accelerated by a cathode @1 pressure by an electric field applied between negative and negative electrodes. , which collides with the target material placed on the cathode, and the constituent atoms or particles of the target material released by the collision of ions adhere and deposit on the substrate provided near the anode to form a thin film of the target material. It is.

Conventionally, a planar magnetron type sputtering apparatus is often used as a sputtering apparatus for performing the above sputtering film formation.

, 3.

FIG. 1 is a cross-sectional view showing the structure of the film forming part of a conventional well-known planar magnetron sputtering apparatus.
FIG. 2 is a cross-sectional view showing the sputtering state near the positive and negative electrodes. Target material (hereinafter referred to as target)
A backing plate 2 is disposed on the back surface of 1 [7, and on the back side thereof, a ring-shaped magnetic pole 4 and a cylindrical magnetic pole 5, which are magnetically coupled by a yoke B, are arranged to constitute a magnetic circuit, and the backing plate 2 includes this magnetic circuit and A cathode 6 having a structure sealed by a plate 2 is installed, and a shield 8 is attached to the outer periphery of the cathode 6 via an annular insulating plate 7. The cathode 6 is installed in a suspended state on a vacuum wall 9 with a shaft 10 fully interposed; it is electrically insulated and maintained in a vacuum, and an anode 11 is arranged above the cathode 6, and a power source 12 is placed between the anode and the cathode. 1. In sputtering with the above configuration, the distribution of magnetic lines of force on the surface of the target 1 becomes a semicircular annular magnetic field distribution 16 as shown in FIG. The generated plasma is highly densely confined inside by the semicircular annular magnetic field distribution 13,
The shape is shown in FIG. 214. The ions in the plasma are accelerated by an electric field substantially perpendicular to the surface of the target 1 and collide with the surface of the target 1. As a result, the atoms or particles are sequentially ejected from the surface of the target 1, forming an eroded region 15.

The atoms or particles of the target 1 that have been repelled as described above adhere to the surface of the substrate 17 on the substrate stage 16, as shown in FIG. 1, to form a thin film.

Furthermore, as is clear from the above explanation, the degree of erosion in the eroded region 15 increases as time passes during the sputtering process, but this erosion normally occurs in a specific target area in the target structure shown in FIG. Proceed in a limited area.

As described above, in conventional planar magnetron sputtering equipment, high plasma density can be obtained only in a small part of the target, and erosion due to sputtering is limited to a part of the target, so target atoms or particles on the substrate are The deposition rate is slow, and only a limited portion of the target is eroded as time passes during the sputtering process, so if this portion becomes eroded a certain amount, the target rattle must be replaced, resulting in a low target usage rate. It had a short lifespan.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, generate high-density plasma over the entire target surface, make the target erosion area in the sputtering process almost the entire target area, and prevent target atoms or particles from reaching the substrate. An object of the present invention is to provide a sputtering method and apparatus for increasing deposition rate and target utilization.

[Summary of the invention]

That is, the present invention is characterized in that the target surface is covered with high-density plasma, the ions in the plasma are caused to collide with the target surface by an electric field, and the atoms or particles ejected from the target are attached to the substrate to form a film. This is a sputtering method.

In addition, the present invention transfers high-density plasma generated by microwave oscillation to the entire target surface, covers the target surface with high-density plasma, and uses an electric field to cause ions in the plasma to collide with the target surface so that they are not repelled from the target. This is a sputtering method characterized by forming a film by making the atoms or particles adhere to the entire substrate.

Further, the present invention uses microwaves (for example, 2.0.
45 Q Hz) to generate high-density plasma, and provide means for transporting this plasma to the positive and negative electrode sections,
By covering the entire surface of the target with high-density plasma, the target erosion region is made to cover the entire target area, thereby reducing the amount of target atoms or particles to the substrate. One embodiment of No. 1 will be explained with reference to FIGS. 3 and 4. FIG. 6 is a cross-sectional view showing the structure of the sputtering film forming part of the first embodiment, and FIG. 4 is a cross-sectional view showing the sputtering state in the vicinity of the positive and negative electrodes. A backing plate 22 is placed on the back surface of the target 21, a cathode 23 is placed in close contact with the backing plate 22, and an anode 27 is placed around the outer periphery of the cathode 23 via a disc-shaped insulator 25 and a cylindrical insulator 26. There is. The anode and cathode electrodes are electrically insulated from the vacuum wall 29 by the shaft 28 of the cathode 23 and installed in a state capable of maintaining a vacuum, and a power source 60 is installed between the anode and cathode electrodes.

Further, the substrate 31 is placed on the substrate holder roller 2 at a position opposite to the target 21, and is attached to the vacuum wall 29 by the shaft roller 6 of the substrate holder 32 in a state where it is electrically insulated and capable of maintaining a vacuum. There is. Further, a window 64 is provided in the vacuum wall next to the positive and negative electrode sections 35, and the high-density plasma generation section A is installed here.

The high-density plasma generation section A is made up of a microwave generation source 35, a waveguide 66 for guiding the microwave, and a waveguide 38 for introducing the microwave into the plasma generation chamber 37. The generation chamber 37 and the waveguide 3B are attached so that the plasma generation chamber 37 is maintained in a vacuum state through the entire microwave introduction member 39. Further, the plasma generation chamber 37 is provided with an atmospheric gas inlet 4O, and the outer periphery is provided with an electron cyclotron resonance condition (microwave frequency 2
．． A magnet 41 with a magnetic field strength of 875 G) is installed on the side of the microwave oscillation source 35 of the microwave introduction member 39, which is used to transmit microwaves to the microwave generation chamber filter 7. Among them, a magnet 42 is installed which has a magnetic field strength that introduces only the polarized wave effective for electron zychrotron resonance.

In the above configuration, when microwaves are oscillated from the microwave generation source 35 of the plasma generation section A, the plasma generation chamber 6
7 is high-density plasma of atmospheric gas (plasma density 1
011 to 1012/7).

By applying a voltage between the positive and negative electrodes by the power supply 30, plasma is generated on the surface of the target 21, and the high-density plasma generated in the plasma generation chamber 37 is transferred to this plasma, and the high-density plasma generated in the plasma generation chamber 37 is transferred to the surface of the target 21. The plasma is also very dense.

The ions in this plasma are accelerated by a nearly perpendicular electric field applied to the surface of the target 21 by the power source 30, and collide with the surface of the target 21. As a result, the atoms or particles are sequentially ejected from the surface of the target 21, and the ejected ions are The above atoms or particles adhere to the surface of the substrate 31 and form a thin film.

As shown in FIG. 4, the plasma on the surface of the target 21 becomes a high-density plasma as shown in FIG.
Covers almost the entire surface of 1.

As described above, according to the first embodiment of the present invention, high-density plasma is generated over the entire target surface and the sputtering process occurs over almost the entire target area, so that the number of atoms or particles ejected from the target surface per unit time is As the amount increases, so does the rate of attachment of the atoms or particles to the substrate.

The eroded area of the splintered target covers almost the entire surface of the target, resulting in a significant increase in target utilization and an increase in the number of wafers processed per target.

Furthermore, according to this example, high-density plasma can be controlled by a microwave source, and the voltage applied between the positive and negative electrodes becomes ion acceleration energy, so plasma density and ion acceleration can be controlled separately. , optimal sputtering conditions can be set according to the target material.

Next, a second embodiment of the present invention will be described with reference to FIG. The high-density plasma generating section of this embodiment is the same as that shown in A of FIG. 3, and the branch relationships of the substrates are also the same. The difference from the first embodiment is the positive and negative electrode parts, and the positive and negative electrode parts of the second embodiment have a backing plate 46 arranged on the back surface of the target 45, as shown in FIG. Closely connected to the cathode 4
7 is installed, and the cathode 17 is sandwiched between all U-shaped parts 11
- An anode base 49 is placed on the bottom surface through an insulator 48, and an anode 52 containing magnetic poles 50 and 51i on the left and right sides is installed on the anode base 49, a yoke 53 is arranged between the anode base 49 and the insulator 48, and the yoke 56 and the magnetic pole 50.degree. 51 are magnetically coupled to form a magnetic circuit. The distribution of these lines of magnetic force on the target surface is as shown in FIG. 5, 54.

In the above configuration, when microwaves are oscillated from the microwave generation source 35 of the plasma generation part A, the plasma generation unit 6
7 is a high-density plasma state of the atmospheric gas, and by applying the full voltage between the positive and negative electrodes, the target 45
A dense plasma is generated on the surface. Here, this plasma is confined inside as a higher density plasma by the magnetic field distribution 54, and becomes as shown in 55 in FIG. As mentioned above, the ions in this plasma are
Atoms or particles are accelerated by a substantially perpendicular electric field applied to the plane 45e and collide with the surface of the target 45, and are ejected from the surface of the target 45, which adhere to the substrate and form a thin film.

, 12° The erosion area of the target 45 according to this embodiment is 56, which is the entire surface of the target. As described above, according to this embodiment, the density of the plasma on the target can be higher than that of the first embodiment, and therefore faster sputtering film formation can be achieved, and since the plasma is confined, 1. Collision of charged particles with the substrate can be reduced, causing less damage to the substrate.

Another embodiment of the present invention will be explained with reference to FIGS. 6 to 8. FIG. 6 is a cross-sectional view showing the structure of the film forming part of the sputtering apparatus of one embodiment, FIG. 7 is a plan view of the vicinity of the positive and negative electrodes, and FIG. 8 is a cross-sectional view showing the sputtering state of the vicinity of the positive and negative electrodes. It is a diagram.

A bagging plate (l/-) 22 is placed on the back surface of the target 21 [1, a cathode 2!1 is installed in close proximity to this, and a disk-shaped insulator 25 and a cylindrical insulator 26 are placed on the outside of the cathode 26.
An anode 27 is installed via the anode 27.

The anode and cathode electrodes are electrically insulated from the vacuum wall 29 by the shaft 28 of the cathode 23 and installed in a suspended state while maintaining a vacuum, and a power source 30 is installed between the anode and cathode electrodes.

Further, the substrate 31 is placed on a substrate boulder 62 at a position facing the target 21, and is attached to the vacuum wall 29 by a shaft 62 of the substrate holder 32 in a state where it is electrically insulated and capable of maintaining a vacuum. In addition, a window 64 is provided in the vacuum wall 57 surrounding the positive and negative electrode parts, and a microwave waveguide 6 is installed in the window 64.
0 is installed, and another waveguide 36 is installed via an introducing member 69 so as to introduce microwaves and maintain a vacuum inside the vacuum wall, and the other end of the waveguide 36 is equipped with a microwave. A generation source 35 is installed. Furthermore, disk-shaped magnets 58 and 59 are installed on the outside of the vacuum walls surrounding the positive and negative electrode sections, sandwiching the waveguide 60 therebetween. The magnet 58.5
9 is a charged particle (
In the above configuration, plasma is generated on the surface of the target 21 by applying full voltage to the positive and negative electrodes "i1" from the power source 3O. Here, microwaves are oscillated from the microwave generation source 35, passed through the entire waveguide 60, and introduced into the vacuum wall 36 from the window 64, causing the electrons in the plasma to become magnets 58, 59. The entire cyclotron movement is accelerated by the microwaves, which activates collisions between electrons and neutral particles and increases plasma density.

As a result, plasma near the positive and negative electrodes is generated on the surface of the target 21 so that high-density plasma covers the entire surface of the target 21, as shown in FIG. The ions in this plasma are connected to the surface of the target 21 by a power source 60.
accelerated by a nearly perpendicular electric field applied by
collides with the surface of target 21, resulting in target 21
The atoms or particles are sequentially ejected from the surface, and the ejected atoms or particles adhere and deposit on the surface of the substrate 31 to form a thin film.

FIG. 8 shows the plasma on the surface of the target 21.

As shown in 61, over the entire surface of the target 21,
Due to the high-density plasma, the erosion area of the target 21 over time during the sputtering process is 6°.
2, covering almost the entire surface of the target 21.

As described above, according to one embodiment of the present invention, high-density plasma is generated over the entire surface of the target, and the sputtering process occurs over almost the entire area of the target, so that the number of atoms or particles ejected from the target surface per unit time is As the amount increases, so does the rate at which the atoms or particles adhere to the substrate. In addition, the erosion area of the target covers almost the entire surface of the target, greatly improving the target usage rate and increasing the number of wafers processed per target.

Furthermore, according to this embodiment, high-density plasma can be controlled by a microwave generation source, and the voltage applied between the positive and negative electrodes becomes an ion accelerating electric field, so plasma density and ion acceleration can be controlled individually. Optimal sputtering conditions can be adopted according to the target material.

〔Effect of the invention〕

・16・ As explained above, according to the present invention, high-density plasma can be generated on the target surface over the entire surface of the target, and plasma generation and ion collision energy with the target can be individually controlled. It is now possible to set sputtering conditions, greatly increasing the speed of sputtering film formation, and greatly increasing the target usage rate. By setting sputtering conditions that still match the target material, it is possible to improve production efficiency and material usage efficiency. This has the effect of improving the performance of semiconductor devices, etc.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the structure of the film forming part of a conventional Brehner magnetron sputtering device. Fig. 2 is a cross-sectional view showing the sputtering state near the positive and negative electrodes of the device.
The figure is a cross-sectional view showing the structure of the film forming part of the sputtering apparatus according to the first embodiment of the present invention, FIG. 4 is a cross-sectional view showing the sputtering state near the positive and negative electrodes, and FIG. FIG. 6 is a sectional view showing the sputtering state near the positive and negative electrodes of a sputtering apparatus according to an embodiment of the present invention; FIG. The figure is a plan view showing the vicinity of the anode electrode, and FIG. 8 is a sectional view showing the state of sputtering in the vicinity of the anode and cathode electrodes. 21... Target 25... Cathode 27... Anode 29... Vacuum wall 30... Power supply Filter 1... Substrate 35... Microwave generation source 37... Plasma generation chamber 39...・Microwave introduction member 41...Magnet 44...Erosion area 50.51...Magnetic pole 45...Target 55...
・Magnetic field distribution 56... Erosion area・ 19・ Figure 1, Figure 2, Figure 4, Figure 43, Figure 5 (0-), Figure 7, 57, Figure 8, Figure 8.

Claims (1)

[Claims] 1. A method of forming a film by covering the target surface with high-density plasma, causing ions in the plasma to collide with the target surface using an electric field, and causing atoms or particles ejected from the target to adhere to the substrate. Characteristic sputtering method. 2. Transfer the high-density plasma generated by microwave emission to the target surface, cover the target surface with high-density plasma, and use an electric field to cause the ions in this plasma to collide with the target surface, causing the atoms or atoms ejected from the target to collide with the target surface. A sputtering method characterized by depositing particles on a substrate to form a film. 3. A target as a film formation source made of a material to be sputtered and facing the deposition surface of the sample substrate at a predetermined distance, a cathode on which the target is placed, a power source for applying voltage to the cathode, and the cathode. What is claimed is: 1. A sputtering apparatus, comprising means for supplying plasma to a part of the sputtering apparatus. 4. The sputtering apparatus according to claim 3, wherein the plasma supply means comprises a microwave generation source, a waveguide, and a plasma generation chamber. 5. The sputtering apparatus according to claim 4, wherein the plasma generation chamber is provided with magnetic poles for obtaining a magnetic field distribution perpendicular to the direction of propagation of the microwaves. 6. The sputtering apparatus according to claim 5, wherein the magnetic pole has a magnetic field strength that satisfies microwave frequency and electron cyclotron resonance conditions. 7. A target as a film formation source made of a material to be sputtered and facing the deposition surface of the sample substrate at a predetermined distance, a cathode on which the target is placed, a power source for applying voltage to the cathode, and the cathode. A sputtering apparatus comprising means for supplying plasma to the surface of the target, and magnetic poles for obtaining a magnetic field distribution parallel to the surface of the target. 8. The sputtering apparatus according to claim 7, wherein the plasma supply means comprises a microwave generation source, a waveguide, and a plasma generation chamber. 9. A target as a film forming source made of a material to be sputtered and facing the deposition surface of the sample substrate at a predetermined distance, a cathode placed on the target rattler, a power source for applying a voltage to the cathode, and the cathode. A sputtering apparatus characterized in that it has a means for introducing microwaves into the substrate. 10. The sputtering apparatus according to claim 9, wherein the entire apparatus is configured to introduce microwaves between targets. 11. The sputtering apparatus as set forth in claim 9 and 10, characterized in that lines of magnetic force are provided perpendicular or parallel to the target surface.